Circuit interrupter



Oct. 17, 1944. JOHNSON 2,360,687

CIRCUIT. INTERRUPTER Filed July 29, 1942 3 Sheets-Sheet l WITNESSES:

lNVENTOR M v Freder/ck 5. J0/7/750/7 MM BY NATTORNE Oct. 17, 1944. F. JOHNSON 2,360,687

CIRCUIT INTERRUPTER Filed July 29, 1942 3 Sheets-Sheet 2 WITNESSES; INVENTOR 1 Freder/c/f 5. Johnson Oct. 17, 1944. F. B. JOHNSON CIRCUIT INTERRUPTER Filed July 29, 1942 3 Sheets-Sheet 3 8 Na Q Q INVENTOR Frederic/f 5. J0/7/750/7 BY Q/ w ATTORN Patented Oct. 17, 1944 CIRCUIT INTERRUPT'ER Frederick B. Johnson,

Pennsylvania Clairton, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Application July 29, 1942, Serial No. 452,686

12 Claims.

This invention relates to circuit breakers, and more particularly to operating mechanisms for circuit breakers of the fluid operated type.

One object of the invention is to provide an improved operating mechanism of the fluid pressure operated type that is simple and rugged in construction and capable of efficient and reliable operation.

Another object of the invention is to provide a fluid pressure actuated operating mechanism for a circuit interrupter wherein compressed gas is admitted alternately to opposite sides of an operating piston by two control valves which are selectively operated by compressed gas admitted thereto by a single selector valve.

Another object of the invention is to provide an improved gas pressure actuated operating mechanism for circuit interrupters embodying a novel elector means for simultaneously shutting off the supply of gas pressure to one side of an operating piston and admitting compressed gas to the other side of the piston to effect a quick reversal of the movement of the piston.

Another object of the invention is the provision of a fluid pressure operated circuit breaker with an improved control valve mechanism which will always cause an opening operation of the circuit breaker to take precedence over a closing operation in the event of conflicting control impulses.

Another object of the invention is to provide an improved gas pressure actuated operating mechanism for circuit interrupters embodying electromagnetically operated valves for controlling the admission of compressed gas alternately to the opening and closing sides of an operating piston in which the opening valve is operable in response to overload currents to automatically shut off the supply of compressed gas to the closing side of the piston and to admit compressed gas to the opening side of the piston irrespective of the energized condition of the closing valve.

The novel features that are considered characteristic of the invention are set forth in parlcular in the appended claims. The invention itself. however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of one embodiment thereof when read in conjunction with the acompanying drawings, in which:

Fig. l is a front elevational view of a gas blast circuit interrupter embodying the principles of the invention;

side elevational view, partly in secinterrupter illustrated Fig. 2 is a tion, showing the circuit in Fig. 1;

Fig. 3 is an elevational view, partly in section, of the operating cylinder of the operating mechanism and the control valves.

Fig. 4 is an enlarged detail View showing the selector valve in operated position.

Referring to Figs. 1 and 2 of the drawings, a storage tank 6 mounted within a metal frame I is provided for storing gas, such as air, under pressure. Extending from the top of the tank 6 are three flanged conduits metallic valve casings ID. A tubular insulator 12 having a gas passage therethrough is mounted on the upper end of each valve casing l0 and an arc chute support 14 (Fig. 2) also of insulating material is secured to the upper end of the tubular insulator l2. The support [4 ha mounted thereon a stationary contact l6 (Fig. 2) provided with an external terminal connector IS. A gas passage extending through the support l4 coincides with the passage through the insulator l2. The passage 20 opens into the bottom of an arc chute 22 secured by means of bolts 24 to the support l4. Braces 25 of insulating material connect the frame I and the insulating brackets I4.

The forward side of the are chute (Fig. 1) is provided with a rectangular opening 26 adjacent the lower end thereof through which a movable contact blade 28 is operated into and out of engagement with the stationary contact I6. One arm 30 of the movable contact is bifurcated and the two legs are pivoted at 32 to a conducting bracket 34 securely clamped about the tubular insulator l2. The pivotal connection 32 is of the high-pressure type in order to provide a good electrical connection at all times between the bifurcated contact arm 30 and the bracket 34. A terminal connector 36 extends from the right-hand side (Fig. 2) of the bracket 34, and serves, together with the terminal connector l8, to connect the interrupter in an electrical circuit. The circuit through the breaker extends from the terminal l8 through the stationary contact IS, the movable contact 28, the contact arms 30, the bracket 34 to the terminal 36.

An operating mechanism of the compressed gas type indicated generally at 38 (Figs. 1 and 2) is provided to actuate the three movable contact arms 3!] about the pivots 32 to open and close the contacts. The operating mechanism 38 is mounted within the frame 1 and includes an 8 which, in turn, carry,

operating cylinder 40 (Figs. 1 and 3) a piston 42 (Fig. 3) reciprocably movable therein, and a connecting rod 44 attached to the piston and extending vertically through the upper end of the cylinder 40. The connecting rod 44 is connected by a pair of spaced link 46 to a crank arm 48 secured to a cros shaft 50 which is journaled in brackets 52 secured to the side of the pressure tank 6.

The crank arms 54, secured at spaced intervals to the cross shaft 56, are connected by insulating operating rods 56 to the movable contact arms 30 for the three poles of the interrupter. If gas under pressure is admitted to the cylinder 40 above the piston 42 the piston will move downwardly in the cylinder and the connecting rod 44 will actuate the crank arm 48 and the cross shaft 50 in a counterclockwise direction. This movement of the shaft 58 rotates the three crank arms 54 in the same direction and, through the connecting rods 56, rotates the movable contact arms 36 about the pivots 32 toward the open circuit position.

Referring to Fig. 2, each of the crank arms 54 is provided with a cam surface 58 which cooperates with a roller 60' carried by one arm of a bell crank 52. The bell crank 62 is pivoted at E4 on a suitable support and the other arm of the bell crank is pivotally connected to a valve stem 66 which carries a blast valve 68 at its lower end. The blast valve 68 is seated within the valve chamber I and normally closes the air blast passage in the insulator I2 from the pressure tank 6. As the three crank arms 54 start to rotate in a counterclockwise direction (Fig. 2), the cams 58 will cause the bell cranks 62 to be rotated in a clockwise direction, thereby operating the valve stems E6 toopen the blast valves I58. Upon opening of the valves 68 a blast of compressed gas from. the storage tank 6 is projected through the hollow insulators I2, through the passages 23 and between the contacts I6 and 28. The configuration of the cam 58 is such that the valve 68 is opened just prior to the separation of the contacts I6 and 28 to insure a blast of armextinguishing gas at the separating contacts when the arc is drawn. The arc drawn between the contacts is thus blown upwardly into the arc chute 22 and there extinguished by the blast of gas from the pressure tank 6. The cams 58 on the crank arms 54 are so shaped that the valves 68 are permitted to close when the moving contacts 28 have reached full open position so as to shut oif the blast of compressed gas.

Upon admission of gas to the cylinder 4?] below the piston 42, the piston will be moved upwardly in the cylinder reversing the above-described operation to operate the moving contacts 28 to closed position. As the mechanism arrives at the closed circuit position the crank arms 54 engage stops 55. In this position the crank arms 54 and their connecting rods 56 form a slightly overcenter toggle which maintains the movable contacts positively locked in the closed circuit position.

In order to effect opening and closing of the circuit interrupter, two control valves indicated generally at IE3 and I2 (Figs. 1 and 3) are provided to control the flow of compressed gas from the storage tank 6 to the operating cylinder 4! The control valve assemblies 70 and F2 are secured to the operating cylinder 4!) and rest upon and are secured respectively to flanges i4 and 16 of two short conduits I8 and 80. The conduits I8 and 8t communicate with relatively larger conduits 82 and 84 which extend through the side of the pressure tank 6 and terminate well within the interior thereof. Each of the conduits 82 and 84 is provided with a partition 85 (Fig. 2) for the purpose of forming auxiliary gas storage compartments 83 and t5, respectively, for supplying the compressed gas used in opening and closing the interrupter. The partitions 86 are mounted on threaded shafts 88 secured at their left-hand ends (Fig. 2) to the outer ends of the conduits 82 and 84. The vol ume of the auxiliary tanks 83 and 85 may be varied to meet certain conditions by changing the locations of the partitions 85 in their respective conduits.

Provision is made to control the replacement of gas from the tank '0 to the auxiliary tanks 83 and B5. The means for accomplishing this control is not shown herein but is fully disclosed in the copending application of Leon R. Ludwig and Benjamin P. Baker, Serial No. 323,214, filed March 9, 1940, and assigned to the assignee of the present invention. Generally, the means for controlling the rate of replacement of gas to the auxiliary tanks 83 and 85 comprises a plurality of passages (not shown) through the partitions 86. These passages may be opened or closed by removing or inserting suitable plugs (not shown) in the openings as a greater or lesser flow of gas is desired.

The valves II? and I2, which respectively control the flow of gas from the auxiliary tanks 83 and 85, are similar in construction. The opening valve iii, shown in section in Fig. 3, comprises a valve casing I64, the lower face of which rests on the flange 14 of the conduit 78. The valve casing W4 is provided with a valve seat I65 with which a valve IE8 of the poppet type cooperates to open and close the air passage leading from the auxiliary tank 83 to the cylinder 40 above the piston 42. The valve IE8 is provided with a valve stem II ii having a washer II 2 secured to its upper end with which a spring I I4 coacts to normally hold the valve closed. The inner chamber of the valve casing I64 communicates, by means of a passage M6, to the upper end of the cylinder 49. The valve casing I IE4 is also provided with a passage I I8 which communicates with the auxiliary chamber 83 and a valve chamber I23 in an auxiliary valve casing I 22.

An electromagnetically operated valve I24 in the casing I22 communicates, by means of a passage Sll, with a selector chamber 92 (Fig. 4) having an electromagnetically operated selector valve 94 reciprocably movable therein. The selector chamber communicates by means of a passage I26 with a piston chamber I28 at the upper end of the opening valve casing Hi4. A piston I30 operable in the chamber I 28 is normally held in raised position by a spring I32. The lower end or skirt of the piston I39 extends to a plurality of ports I34 passing radially through the side of the valve casing I04. When the piston I30 is in the raised position (Fig. 3) the ports I34 are open, thereby connecting the space in the operating cylinder 40 above the piston 42 to the atmosphere. Downward movement of the piston I30 closes the ports I34 and thereby seals the passage H6 and the cylinder 45 from the atmosphere and moves the main valve N38 to open position.

The selector valve element 94 is provided with three passages 95, 96 and 98 and an auxiliary passage I99 and is adapted to be operated from the position in which it is shown in Fig. 3 to the position shown in Fig. 4 by means of a tripping electromagnet I92. With the magnet I92 unenergized, the selector valve 94 rests in the bottom of the selector chamber 92. In this position the passage 96 in the selector valve 94 connects the passage 99 to a passage 91 in the casing I22 above the valve casing I94. The passage 91 communicates by means of a conduit 99 to the piston chamber (not shown) in the closing control valve I2.

When the selector valve 94 is in the lower position (Fig. 3) the lower end of the passage 98 is aligned with the passage I26 and the upper end of the passage 98 is aligned with an exhaust port I9I extending through the bottom leg of a U-shaped bracket I93 which supports the electromagnet I92, thus connecting the piston chamber I28 of the opening valve 19 with the atmosphere.

Pivotally mounted at I56 (Fig. 3) in projections I58 of the bracket I93 is a lever I69 having one end disposed above and adjacent to the upper end of the selector valve element 94. The other end of the lever I69 normally rests on a manual closing button I62 depressibly supported on a magnet frame I64. The magnet frame is securely mounted on the outer end of the valve casing I22 and rigidly supports a closing electromagnet I36. The valve I24 is actuated downwardly to open position by the eleotromagnet I36 which may be energized by a suitable source of electrical energy (not shown), and is moved upwardly to the closed position by a spring I38.

When the interrupter is in the closed circuit position, the operating mechanism, including the piston 42 is in the position shown in Fig. 3. With the mechanism in this position, if an overload occurs, or if it is desired to open the interrupter for any other reason, the trip magnet I92 is energized. The energizing circuit of the electromagnet I92 may be controlled by an opening relay and by an auxiliary switch I49 (Fig. l) of any suitable construction mounted on the tank 6.

Upon energization of the trip magnet I92, the selector valve 94 is shifted upwardly in the chamber 92 to the position shown in Fig. 4 in which the passage 95 of the valve is in alignment with the passages 99 and I25, thus forming a clear passage from the valve chamber I29 to the piston chamber I28 of the opening valve. When the valve 94 is moved to its upper position the passage I99 forms a connection between the passage 91 and the exhaust port I9 I as shown in Fig.

4, thus connecting the piston chamber (not shown) for the closing valve I2 to the atmosphere through the conduit 99, passages 91, I99 and IN. When the valve 94 moves upwardly, upon energization of the magnet I92, the upper end thereof engages and rocks the lever I69 clockwise about its pivot I55. The lever I69 engages and operates the button I62 to open the valve I24 and permit air under pressure within the auxiliary tank 83 to flow through the passage II8, through the valve I24, passages 99, 95 and I26 into the piston chamber I28 of the opening valve. The piston I39 is thereupon moved downwardly against the force of the spring I32, thereby closing the ports I34 and opening the valve I98. The piston I39 is so disposed with respect to the upper end of the valve stem H9 that the ports I34 are substantially closed by the time the piston engages the valve stem. Opening of the valve I98 permits compressed gas from the auxiliary tank 83 to flow through the passage II6 to the space in the cylinder 49 above the operating piston 42, moving the piston downwardly to actuate the breaker contacts 28 to the open circuit position in the manner previously described.

When the breaker reaches full Open position, the auxiliary switch I49, which is connected by a linkage I42 to the connecting rod 44, is actuated to open the energizing circuit of the trip magnet I92 allowing the valve I24 to close. Deenergization of the magnet I92 also permits the selector valve 94 to move to its normal position as shown in Fig. 3, thus connecting the chamber I28 with the atmosphere. A small exhaust port I25 connects the chamber 92 below the selector valve 94 to the atmosphere to exhaust the air pressure below the valve as it moves downwardly in the chamber 92. When the pressure has been reduced in the chamber I28, the springs H4 and I32 expand and cause the piston I39 to move upwardly and at the same time cause the valve I98 to close. In order that the mainpiston 42 may move downwardly at a very high rate of speed so as to efiect opening of the contacts as quickly as possible, a relatively high gas pressure is essential at the beginning of the opening stroke. This has been accomplished by providing the auxiliary tank 83 of such volume as to produce'the desired result. To reduce shock at the end of the opening stroke, but without sacrificing speed of operation, the force acting on the main piston 42 decreases as the movement of the piston increases. As the piston 42 is moved to the open circuit position, the air pressure within the auxiliary tank 83 decreases during the short interval of time required for the mechanism to reach full open position. This decrease of pressure in the auxiliary tank 83 is efiected by making the passage through the partition 86 (Fig. 2) relatively small to avoid substantial replacement of the air pressure Within the auxiliary tank 83 from the main tank 6 during the opening operation. By providing the proper number of passages, the proper rate of flow of air from the main tank 6 into the auxiliary tank 83 may be obtained.

By using a limited quantity of a r to effect the opening operation, the piston and operating mechanism may be brought to rest without too much impact or shock. It is desirable, however, to provide shock absorbing means in order to absorb the kinetic energy of the moving parts. The kinetic energy at the end of the opening stroke is absorbed by controlling the discharge of air ahead of the piston 42. The degree of compression, particularly at the end of the stroke, may be controlled and utilized to provide a shockabsorbing cushion for arresting the movement of the p ston and the connected moving parts. The escape of air ahead of the piston is controlled by the ports I34 through the side of the valve casing I94 of the closing central valve I2. The construction of the control valve I2 is similar to the control valve '19. When the valve I9 is opened for admitting air to the operating cylinder 49 to effect opening of interrupter, the valve I2 is closed. The ports !34 of the control valve I2 both as to number and size are arranged so that the air ahead of the piston during the opening operation reaches a predetermined compression at the end of the opening stroke. This condition of compression ahead of the piston 42 persists but only for a short time as the ar is quickly exhausted from the cylinder 49 through the ports I34. When the piston 42 reaches full open-circuit position and control Valve 70 is closed due to the deenergization of the electromagnet I02, the air above the piston 42 is quickly exhausted through the passage I I6 and the ports I 34 in the control valve I so as to permit a reclosing operation of the interrupter by admission of air to the lower side of the piston 42 through the valve 72.

When it is desired to close the interrupter, the electromagnet I36 is energized through the auxiliary switch E46. Energization of the magnet I36 opens the valve I24 and, since at this time the magnet I02 is not energized, the selector valve G4 remains in its lower position (Fig. 3) wherein the passage 96 connects the passage 96 with the passage 91 and the conduit 99 to admit air from the auxiliary tank 83, through the passage I I8, valve I24, passages 92, 9S and 91 and through the conduit 99 to the valve I2. This opens the valve 72 so as to admit air from the auxiliary tank 85 to the lower side of the operating piston 42. The valves Ill and I2 are identical in construction for which reason it, is not deemed necessary to further describe the valve 12. During the closing operation, the air above the piston 42 is compressed by the moving'pisto-n 42 to provide a pneumatic cushion for arresting the movement of the piston 42. The proper degree of compression is obtained by the selection of the size and number of exhaust ports I34 provided in the casing of the opening control valve l6. Upon reaching the closed circuit position, or at a predetermined time during the closing operation, the auxiliary switch I 41] interrupts the circuit to the electromagnet I35 permitting the valve I24 to close which, in turn, permits the valve I2 to close in the manner described in connection with the description of the valve Ill.

The interrupter may be closed manually by depressing the manual closing button I52. Depression of the button I62 opens the pivot valve I24 and admits compressed air through the previously described passages including the conduit 99 to operate the closing control valve I2. This admits compressed air into the cylinder 49 below the operating piston 42 to actuate the piston and the connected operating mechanism to closed position.

If the interrupter is closed while an overload exists on the circuit controlled by the interrupter, it is necessary that the direction of motion of the piston 42 be quickly reversed in order to actuate the interrupter to open circuit position. To accomplish this quick reversal it is necessary to quickly exhaust the pressure under the piston 42. For this purpose a quick release valve I44 (Fig. 3) is provided at the bottom of the cylinder 4-0. The valve I44 is carried on a stem. I46 slidable vertically through a suitable opening in the bottom of the cylinder 40 and is biased to closed position by a spring M8. The valve I44 is adapted to be moved to open position by means of an operating rod I 50 secured at its lower end to the valve I 44 and having at its upper end a slidable connection with the connecting rod 44. The slidable connection comprises a head I 52 on the upper end of the rod, which is slidable in the bore of the connecting rod 44. The head I52 is adapted to be engaged by a packing and guide sleeve I54 threadedly engaging the lower end of the connecting rod 44. The operating rod 150 is of a length such that when the piston 42 reaches the upper limit of its travel, the valve M4 will be fully opened, thereby quickly exhausting the air below the piston 42 to the atmosphere. Thus it can be seen that the piston 42 is free to move downwardly under normal conditions of operation. Only a short travel in a downward direction is required of the piston 42 before the valve I44 is closed, thereby permitting the air under the piston to be compressed for the purpose of cushioning the piston at the end of its opening stroke.

Heretofore in compressed air operating mechanisms of the type disclosed, the movement of the operating piston Was controlled for opening and closing movements by electromagnetically operated valves, one for admitting air to the opening side of the piston, and the other for admitting compressed air to the closing side of the piston. Since these valves were electrically operated, a condition was possible in which both electromagnets might be energized at the same time, thus admitting compressed air simultaneously to both sides of the operating piston. If pressure were admitted on both sides of the piston 42, the operating mechanism would become inoperative and no movement either in opening or closing direction would occur, and the moving contacts may become stationary at any point of their travel. The purpose of the interrupter is to provide protection for the circuit controlled thereby, and it is necessary to insure high speed opening movement of the operating mechanism under the adverse condition of conflicting control impulses. This quick reversal of the movement of the operating mechanism and high speed movement thereof in opening direction is accomplished by the provision of the novel selector valve 94.

Assuming that the interrupter has been opened and that the closing magnet I36 is energized to operate the closing control Valve 12. If, during the upward movement of the operating piston 42, the trip magnet I02 is energized, the selector valve 94 will be immediately moved to its upper position. This movement of the selector valve simultaneously connects the passages and I26 by means of the passage 95 to admit air pressure to the piston chamber I28 of the opening valve In and closes the passage 909'I for energizing the closing control valve 12. At the same time the passage I89 (Fig. 4) in the selector valve connects the closing valve I2 to atmosphere per mitting quick retrieving of the piston I30 for the valve I2 thereby quickly shutting off the supply of compressed air to the under side of the contact operating piston 42 and opening the ports H34 for the closing valve I2 to permit bleeding of the pressure below the contact operating pis ton. It will be obvious that under such abnormal condition of simultaneous energization of both control valves, the direction of movement of the operating piston 42 and the connected operating mechanism will be quickly reversed and the movable contacts driven to full open position at high speed. It will be further obvious that the above described mechanism is, in effect, trip-free when the interrupter is closed with an overload condition on the circuit controlled thereby.

Some circuit interrupter operating mechanisms of the compressed fluid type employ manually operable means to initiate both opening and closing operations of the interrupter. In such devices it is possible, by inadvertently operating both the closing and the opening control devices at the same time, to admit air pressure to both sides of the operating piston which may result in immobilizing the movable contact in a dangerous partially opened position. The provision of the selector valve 94 obviates this condition. If the closing button 162 is manually operated and held in its operated position to efiect closing of the interrupter and the magnet I02 is energized either under manual control or automatically the selector valve 94 is immediately operated to deenergize the closing control valve 12 and energize the opening control valve I in the previously described manner. This quickly reverses the direction of movement of the operating piston 42 and the connected operating mechanism and moves the movable contact to full open position.

Having described a preferred embodiment of the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details thereof without departing from some of the essential features of the invention. It is, therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

I claim as my invention:

1. In a circuit interrupter, separable contacts, operating mechanism including a cylinder and a piston operable therein for moving said contacts to open and closed positions, a source of 1 gas under pressure, opening and closing control valves operable by compressed gas to admit gas under pressure to said cylinder to cause the piston to move to open or closed position, a pilot valve operable to admit compressed gas to the control valves to operate said control valves, and means comprising a selector valve operable to selectively determine which one of said control valves is to be operated and also operable at times to operate the pilot valve. 7

2. In a circuit interrupter, separable contacts, operating means including a cylinder and a piston operable therein for moving said contacts to open and closed positions, a source of gas under pressure, opening and closing control valves for alternately admitting gas under pressure from said source to opposite sides of said piston to cause said piston to move to open and closed positions, an electromagnetically operated pilot valve operable to admit compressed gas for energizing said opening and closing control valves, means comprising a selector valve operable to determine which one of said control valves is to be energized, and means relating said selector valve to said pilot valve to effect opening of said pilot valve upon operation of said selector valve.

3. In a circuit interrupter, separable contacts, operating means including a cylinder and a piston operable therein for moving said contacts to open and closed positions, a source of compressed gas, opening and closing control valves operable by compressed gas to admit compressed gas to said cylinder to cause the piston to move to open or closed position, an electromagnetically operated pilot valve operable to admit compressed gas to the control valves to operate said control valves, and means normally directing the compressed gas to operate the closing control valve, said means being operable in response to predetermined abnormal circuit conditions to direct the compressed gas to operate the opening control valve and to shut off the compressed gas from the closing control valve.

4. In a circuit interrupter, separable contacts, operating means including a cylinder and a piston movable therein to open and closed positions, a source of gas under pressure, opening and closing valves for alternately admitting gas under pressure to opposite sides of said piston for moving said piston to open and closed position, a selector valve, a pilot valve operable to-admit gas under pressure from said source to the selector valve, said selector valve being operable to direct the gas under pressure from the source alternately to the opening and closing valves, and means operated by the selector valve to operate the pilot valve.

5. In a circuit interrupter, contact means, operating means including a cylinder and a piston movable therein to open and closed positions, a source or" gas under pressure, opening and closing control valves for alternately admitting gas under pressure to opposite sides of the piston for moving said piston to open and closed positions, a selector valve for directing gas under pressure to alternately energize the control valves, an electromagnet for operating said selector valve, a pilot valve between the source and the selector valve, said pilot valve being operable by said selector valve to admit gas under pressure to said selector valve, and an electromagnet for operating thepilot valve independently of the selector valve to admit gas under pressure to the selector valve.

6. In a circuit interrupter, contact means, operating means including a fluid motor operable in opening and closing directions to move said contacts to open and closed positions, a source of fluid under pressure, opening and closing control valves for admitting fluid under pressure to operate the motor in opening and closing directions, a selector valve normally in a position to direct fluid under pressure to energize the closing valve and operable to a position to direct the fluid under pressure to energize the opening valve and simultaneously to connect the closing valve to the atmosphere, a pilot valve for controlling the admission of fluid under pressure to the selector valve, and means operated by the selector valve for operating said pilot valve.

7. In a circuit interrupter, contact means, operating means comprising a fluid motor operable in opening and closing directions for actuating said contact means to open and closed positions, a source of fluid under pressure, fluid pressure actuated opening and closing valves for alternately admitting fluid under pressure to the motor for causing operation of the motor in opening and closing directions, a selector valve having a passage normally connecting the closing valve to the source for energizing said closing valve, said selector valve normally deenergizing the opening valve, a pilot valve intermediate the source and the selector valve, electroresponsive means for opening the pilot valve to thereby energize the closing valve and cause movement of the motor in closing direction, and a tripping electromagnet operable in response to overload currents in the circuit for operating the selector valve and the pilot valve to simultaneously energize the opening valve and deenergize the closing valve to thereby cause movement of the motor in opening direction.

8. In a circuit interrupter, contact means, operating means comprising a fluid motor operable in opening and closing directions to move the contact means to open and closed positions, a source of fluid under pressure, opening and closing valves for alternately admitting fluid under pressure to the motor for causing operation of the motor in opening and closing directions, a selector valve having a passage normally connecting the closing valve to the source for energizing said closing valve, said selector valve normally deenergizing the opening valve, a pilot valve intermediate the source and the selector valve, a closing electromagnet operable when energized to open the pilot valve to thereby energize the closing valve and cause movement of the motor in closing direction, and a trip device including electroresponsive means operable in response to overload currents for operating the selector valve to cause energization of the opening valve to thereby cause movement of the motor in opening direction irrespective of the energized condition of the closing magnet.

9. In a circuit interrupter, contact means, operating means including a fluid motor operable to actuate the contact means to open and closed positions, a source of fluid under pressure, opening and closing control valves for admitting fluid under pressure directly from said source to said motor to operate the motor in opening and closing directions, independently operable means for each control valve including a cylinder and a piston movable therein for operating the opening and closing valves, a selector valve operable to simultaneously direct fluid under pressure to one of said cylinders and to exhaust the pressure from the other of said cylinder to atmosphere to thereby quickly reverse the direction of operation of the fluid motor, and a pilot valve operable by said selector valve and also operable independently of said selector valve to admit fluid pressure to said selector valve.

10. In a circuit interrupter, contact means, operating means including a fluid motor operable to actuate the contact means to open and closed positions, a source of fluid under pressure, opening and closing control valves disposed in passages directly communicating said source to opposite ends of said motor, said valves being operable to admit fluid under pressure to said motor to operate the motor in opening and closing directions, independently'operable means for each control valve including a cylinder and a, piston movable therein for operating the opening and closing control valves, a pilot valve between said source and said valve cylinders and operable to admit fluid pressure to said valve cylinders, a selector valve normally establishing communication between the pilot valve and the cylinder of the closing valve and operable to quickly interrupt the communication between the pilot valve opening valve cylinder to operate the opening valve, and an electromagnet for operating the selector valve.

11. In a circuit breaker, contact means, oper ating means including a fluid motor operable to actuate the contact means to open and closed position, a source of fluid under pressure, opening and closing control valves for admitting fluid under pressure to said motor to operate said motor in opening and closing directions, inde pendently operable means for each control valve including a cylinder and a piston movable therein for operating the opening and closing control valves, a pilot valve between said source and said valve cylinders for controlling the admission of fluid pressure to said cylinders, a selector valve normally establishing communication between the pilot valve and the cylinder of the closing valve and operable to interrupt said communication and to establish a communication between the pilot valve and the opening valve cylinder, said selector valve also being operable to exhaust the pressure from the closing valve cylinder to atmosphere, and an electromagnet for simultaneously operating the selector valve and said pilot valve to admit fluid pressure to the opening control valve cylinder.

12. In a circuit breaker, contact means, operating mechanism including a fluid motor operable to actuate the contact means to open and closed positions, a source of fluid under pressure, opening and closing control valves for admitting fluid under pressure to said motor to operate the motor in opening and closing directions, independently operable means for each control valve including a cylinder and a piston movable therein for operating the opening and closing control valves, a pilot valve between said source and the valve cylinders, a selector valve normally establish-ing communication between said pilot valve and the closing valve cylinder, an electromagnet operable when energized to interrupt said communication between said pilot valve and the closing valve cylinder and to establish communication between the pilot valve and the opening valve cylinder to operate the opening valve, and means operable by said electromagnet to operate the pilot valve.

FREDERICK B. JOHNSON. 

